This proposal is a continuation of the training grant in Structural Biology of the Graduate Group in Biophysics at UCSF (GM08284). The program emphasizes interdisciplinary training at the interface of biology, physics and chemistry. A hallmark of the program is its use of structural experiment and computation to attack fundamental questions of intermolecular interactions, enzyme mechanisms and cell processes. The predoctoral students in the program rank among the best of any program at UCSF, and enter the program with backgrounds ranging from physics and chemistry to engineering, mathematics and biology. Their interests span a wide range of areas including structure-based drug design, the biochemical basis of disease, structural cell biology and macromolecular engineering. Training consists of a core curriculum, a minimum of three laboratory rotations, extensive practice in presenting journal clubs and research talks, an oral qualifying exam, and thesis research. Students completing this training are well prepared to bring their excellent skills and quantitative backgrounds to the solution of the most challenging problems in biomedical research. The proposal requests funding for thirteen positions.